Faraday to George Biddell Airy   4 December 1860

Royal Institution | 4 Decr. 1860.

My dear Sir

I do not know how to render the dark part of the fish tail flame luminous whilst the other parts are retained unchanged in form extent & brightness¹. By mixing some air with the gas before hand you will change the character of all the parts. I can judge only very imperfectly of the flame & its conditions not knowing exactly what you require - I suppose putting the flame edgeways so that the bright & obscure parts should mutually cover each other would not serve your purpose[.] Practically you have as much light from the flame in one direction as in the other[.]

Many thanks for your note about the light house lamp²[.]

Ever Most truly Yours | M. Faraday

G.B. Airy Esqr | &c &c &c